Dicopper oxide

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Already evaluated by the Competent Authority for Biocides and Existing Substances Regulations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

The following minor deviations from OECD Test Guideline 406 (adopted 17 July 1992) were noted:
• No justification is given for the choice of vehicle,
• Dermal reactions were not scored after the intradermal or topical inductions,
• Positive control studies, although conducted, were not reported.
These deviations are not considered to have influenced the outcome or the integrity of the study.

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The available study was conducted prior to the date on whch the LLNA became the method of choice.

Test material

Test material information

Constituent 1

Reference substance name:

Dicopper oxide

EC Number:

215-270-7

EC Name:

Dicopper oxide

Cas Number:

1317-39-1

Molecular formula:

Cu2O

IUPAC Name:

copper (I) oxide

Details on test material:

Lot/batch number: Batch No. 3557
Description: Red powder.
Purity: 88% Cu. 98.8% Cu20.
Stability:
Active substance - the Certificate of Analysis indicates that the tests substance is stable when stored in cool dry conditions.
Dosing preparations - no stability analysis was conducted.

In vivo test system

Test animals

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

Source: Winkelmann, Versuchstierzucht, Gartenstr. 27, W-4799 Borchen, Germany.
Age/weight at study initiation: Upon arrival males weighed 302 to 498 g, and females weighed 301 to 471 g. No information on the age of animals is given.

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

other: Intradermal injections: 0.5 % Na-carboxy methyl cellulose (CMC). Dermal applications: Vaseline.

Induction 2

Concentration / amount:

Concentrations used for induction: Intradermal induction - 0.25% w/w in CMC. Topical induction - 50% w/w in Vaseline (this appears to be the
highest achievable concentration).
Concentrations used for challenge: 50 w/w in Vaseline.
Concentration Freunds Complete Adjuvant (FCA): Freund’s Complete Adjuvant (FCA) 50% w/w diluted in aqua ad inject.

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: Intradermal injections: 0.5 % Na-carboxy methyl cellulose (CMC). Dermal applications: Vaseline.

Challenge 2

Concentration / amount:

Concentrations used for induction: Intradermal induction - 0.25% w/w in CMC. Topical induction - 50% w/w in Vaseline (this appears to be the
highest achievable concentration).
Concentrations used for challenge: 50 w/w in Vaseline.
Concentration Freunds Complete Adjuvant (FCA): Freund’s Complete Adjuvant (FCA) 50% w/w diluted in aqua ad inject.

No. of animals per dose:

Number of animals per group: 4 sighting animals, 20 test animals, 20 control animals.

Details on study design:

Study type: Adjuvant study.

A pretest was performed on irritant effects.

Induction Schedule: Day 0 - Intradermal induction. Day 7 - Topical induction. See Table 1 ('Other information on materials and methods') for an
outline of the treatment schedule.

Challenge Schedule: Day 21 - Topical challenge. See Table 1 ('Other information on materials and methods') for an outline of the treatment schedule.

Rechallenge: No.

Scoring schedule: 24 and 48 hours after challenge.

Removal of the test substance: Not described.

Challenge controls:

Positive controls: The reaction of the positive control substance 2,4 dinitrochlorobenzene (extreme sensitiser) and benzocaine (moderate sensitiser) was tested periodically.

Positive control substance(s):

yes

Remarks:

2,4 dinitrochlorobenzene and benzocaine

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

19

Clinical observations:

One animal from the test group and one animal from the control group died during the challenge procedure.

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 19.0. Clinical observations: One animal from the test group and one animal from the control group died during the challenge procedure..

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

19

Clinical observations:

One animal from the test group and one animal from the control group died during the challenge procedure.

Remarks on result:

other: see Remark

Remarks:

Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 19.0. Clinical observations: One animal from the test group and one animal from the control group died during the challenge procedure..

Any other information on results incl. tables

Results of pilot studies:

Intradermal Induction

Skin reactions were observed after the injections of the test article at the concentration of 5 % (swelling, dark colouration, necrosis), 1 % (redness, necrosis) and 0.5 % (slight redness). No skin reactions were seen at the concentration of 0.25 %.

Topical Induction

No skin reactions were observed after the application of the test article (50 % w/w in Vaseline).

Results of test:

24h after challenge

0/19* animals with allergenic reactions. *One animal of the test group died during the challenge procedure.

48h after challenge

0/19* animals with allergic reactions. One animal of the test group died during the challenge procedure.

Other findings:

Mortality

One animal from the test group as well as one animal from the control group died during the challenge procedure (24 hours after patch removal). The test report does not offer an explication for these deaths.

Body weight

Some control and test animals showed reduced body weight gains or decreased body weight.

Overall result: Under the conditions of this test, cuprous oxide produced a 0% (0/19) sensitisation rate.

Table 2. Results of the skin sensitisation test.

	Number of animals with signs of allergic reactions / number of animals in group
	Negative control	Test group
scored after 24h	0 /19	0 / 19
scored after 48h	0 / 19	0 / 19

One animal from the test group as well as one animal from the control group died during

the challenge procedure (24 hours after patch removal).

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Under the conditions of this test, cuprous oxide produced a 0% (0/19) sensitisation rate.
Cuprous oxide did not meet the criteria for classification as a sensitiser by skin contact according to labelling regulations outlined in Annex VI of
Commission Directive 2001/59/EC.

Executive summary:

Materials and Methods

 

This study was conducted according to GLP, and to OECD Test Guideline 406 ‘Skin sensitisation’ (adopted 17 July 1992). Only minor deviations from test guideline occurred. These deviations are not considered to have influenced the outcome or the integrity of the study.

 

In a skin sensitisation study by the maximisation method of Magnusson and Kligman, 20 control and 20 treated Pirbright white guinea pigs were tested according to the dosing regime described below:

 

Intradermal Induction

An area of 4 x 6 cm over the shoulders was clipped short with electric clippers and cleaned with 70 % (v/v) ethanol. Three pairs of intradermal injections were then made symmetrically in two rows on either side of the spine:

Test group

1. 0.1 ml FCA 50 % (w/w) diluted in aqua ad iniect*

2. 0.1 ml test article diluted in CMC (final concentration 0.25%)

3. 0.1 ml test article diluted in FCA/CMC (final concentration: 0.25%)

Control group:

1. 0.1 ml FCA 50 % (w/w) diluted in aqua ad iniect*

2. 0.1 ml undiluted

3. 0.1 ml CMC 50 % (w/w) diluted in FCA

* As given in test report. However though to be ‘aqua ad inject’.

 

Topical Induction

7 days after the intradermal injections, dermal application was initiated. As the test article was non-irritating at the highest permissible concentration in the pilot study, the area was reclipped and pre-treated with 10 % sodium lauryl sulphate in Vaseline 24 h before application of test article at a concentration of 50 % in Vaseline. The test article was spread into a thick layer over a 4 x 5 cm patch (filter paper). The latter was firmly secured over the previous injection sites by an occlusive dressing for 48 h. Control animals received a patch loaded with vehicle alone.

 

Challenge

Both control and test animals were subjected to challenge exposure 14 days after the topical induction. The challenge test was performed on a 5 x 5 cm clipped area of each flank. The maximal non-irritating concentration of the test article (50 % in Vaseline) was applied to the left flank and the vehicle to the right flank using the patch technique described above. In each case the duration of exposure was 24 h under an occlusive dressing.

 

24 and 48 hours after patch removal, the treated skin areas were evaluated on a numerical scale according to Draize (see attached Figure 1).

 

 

Results and Discussion

 

Induction

Dermal reactions were not scored after the intradermal or topical inductions.

 

Challenge

One animal from the test group as well as one animal from the control group died during the challenge procedure (24 hours after patch removal). The test report does not offer an explanation for these deaths.

 

Some control and test animals showed reduced body weight gains or decreased body weight.

 

There were no signs of irritation in any control or test animal at 24 or 48 hours following dermal challenge treatment.

 

See Table 2 ('Other information on results').